Field of the Invention
This invention relates to electronic screening of transponder-bearing units and, more particularly, to the electronic screening of vehicles using a road or highway system.
Highways and roads are the backbone of the transportation system of most developed or developing countries. While other modes of transportation, such as aircraft, trains, and marine vessels may be used, highways and roads are generally pervasive and available to all citizens for use.
As a result of the large network of highways and the locations that are reachable using them, trucking is one of the most often-used modes of transportation for shipping goods, materials for goods, etc., and thus trucks contribute significantly to the wear-and-tear on the roads and, by virtue of their sheer numbers, are frequently involved in accidents while using the roads. Trucks are typically quite large (i.e., in excess of 80,000 lbs.) and thus can be dangerous if improperly handled or operated in an unsafe condition; in addition, their great weight can cause rapid deterioration of pavement and other road surfaces.
To protect citizens, both physically and fiscally, the Federal government and most states regulate the trucking industry to ensure that the vehicles operating on their roads are in good working order. Further, most states collect taxes from trucking companies and truck owners based on the weight of the truck and of the goods transported by truck, so that trucks contributing to the deterioration of the road (and the resulting need for maintenance) pay their fair share of the costs of repairing and maintaining the roads.
To be able to properly regulate the trucking industry, weight/inspection stations are utilized on most highways. Signs direct trucks to pull into the stations to have their weight checked to ensure that the trucks are in compliance with federal and state weight regulations. These stations use static scales, which require that the truck pull onto the scale and stop while being weighed.
While the vehicle is slowing and stopped on the scale, law-enforcement personnel can inspect and check it for proper credential decals and other obvious safety problems. If any problems are observed, the driver is asked to pull into an inspection area at the site for a more thorough examination. Law enforcement personnel typically may direct a small random sample of vehicles to pull into the inspection area for a more thorough examination, even without observing obvious safety problems. This serves as a check on vehicles that otherwise look to be in compliance with the laws and regulations, and gives the drivers and truck owners an incentive to keep their vehicles maintained in compliance with the laws and regulations to avoid being caught out of compliance.
The weighing process alone can result in delays of 30 seconds to five minutes or more. The inspection process can increase this time to in excess of 30 minutes. These delays can represent a significant cost to trucking operations, particularly in situations where “just-in-time” shipping is being utilized and delays can result in reduced revenues. At some high traffic stations, the queue can back up onto the highway, forcing temporary closure of the station to avoid a safety hazard. Periods when the station is closed provide no enforcement for the trucks that are bypassing the station.
To improve the process, “electronic screening” systems (“e-screening”) have been developed. Electronic screening is the application of technology to make more informed screening decisions. Properly implemented, electronic screening results in improved traffic flow, focuses the vehicle inspections, and ultimately achieves the goals of increased safety and reduce operating costs.
An example of a prior art electronic screening system is “PrePass” (www.prepass.com). PrePass is a system that allows participating transponder-equipped commercial vehicles to bypass designated weigh stations and other such facilities. A vehicle participating in the PrePass system is identified in a database proprietary to the PrePass system, as part of the pre-certification process conducted when the vehicle is registered in the system. The database contains weight information and “credential information” regarding the vehicle and correlates this information with a PrePass transponder ID number that corresponds to a transponder carried in the vehicle.
As a vehicle approaches a PrePass-equipped weight/inspection station, it comes into the range of an Automatic Vehicle Identification (AVI) antenna, which communicates with the transponder to identify the transponder ID number, thereby giving the PrePass system access to the saved data for that vehicle. At the same time, the vehicle passes over a WIM scale, and the weight data obtained from the scale is also transmitted back to the PrePass system. This allows the PrePass system to verify that the vehicle should be able to bypass the inspection station. Assuming everything is verified, a signal is sent to the transponder causing it to issue an audible signal and “go” indication (e.g., a “green light”) directing the driver to pass the station without needing to stop.
An e-screening system concept that complies with the architecture of the “CVISN” architecture prescribed by the Federal Motor Carrier Safety Administration is described in “Introductory Guide to CVISN”, §2.7 The CVISN e-screening concept has many advantages because of its use of a standardized national database that is shared among the states with data and methods of exchange that are standardized according to CVISN architecture. While having many advantages when compared to PrePass, both of these suffer from some disadvantages. Mainline screening alone, based upon AVI, is largely ineffective because it cannot reach the vast majority of trucks that do not operate with a transponder. Mainline screening systems must send all the vehicles that do not have transponders into the weigh station. At many stations, queuing backups would not be alleviated until at least 30–50% of the mainline vehicles were bypassed. Currently, on the order of 1–2% of commercial vehicles carry transponders, so e-screening systems designed around mainline screening alone cannot be effective. Additionally, mainline (i.e., highway-based) WIM scales are inherently inaccurate because the trucks are operating at highway speeds when being weighed using the mainline WIM scale. Vehicle dynamics generated by bumps in the highway road surface and the path of the vehicle contribute to inaccuracies when using mainline WIM scales. As a result, even the transponder-equipped vehicles tend to be directed into the weigh/inspection station to be subjected to the more rigorous and time-consuming static weighing system and detailed inspection process, only to be found in compliance and redirected back to the highway after significant (and unnecessary) delay.
It is desirable to have an e-screening system that can conduct a secondary screening process, based upon AVI and alternative vehicle-identification technology after an initial (primary) screening process to reduce the number of vehicles that are subjected to the time-consuming static-scale weighing process improperly due to the inaccuracies inherent in mainline WIM scale measurements.